1. Field of the Invention
The present invention relates to a light emission control system for controlling light emissions of a flash device, wherein the control system is capable of emitting a preliminary flash emission before a main flash emission.
2. Description of the Related Art
Conventional cameras having a light emission control system for a flash device (electronic flash) in which the amount of light of the main flash discharge is controlled in accordance with photometric readings taken at a pre-flash emission stage (preliminary flash emission), which is emitted before the main flash discharge, are known in the art. However, in a camera in which “split” photometering is possible, it is difficult to photometer the entire photometering area by a single preliminary flash emission.
A light emission control system for a flash device in which a stop timing of light emission of the flash device is controlled with no pre-flash emission with a TTL (through-the-lens) direct photometering system that receives light reflected by a film plane at a time of exposure is known in the art. Such a light emission control system is disclosed in Japanese Unexamined Patent Publication No. 08-248468.
However, in the case of an electronic still camera (i.e., digital camera) which incorporates an image pick-up device such as a CCD image sensor or a CMOS image sensor, it has been proved that a sufficient photometric output cannot be obtained through the TTL direct photometering system because of the low reflectivity of the light-receiving surface of the image pick-up device. Therefore, a TTL direct metering for flash photography is difficult to be performed in conventional electronic still cameras.